Flat Booking Cancellation prior to any Builder-Buyer Agreement or any sale deed signing

Hello Sir, I had made a booking in one of the under construction property in A wing and filled just the booking form and made a initial payment of 10% of the purchase value that is around 10 lakh. During the time of purchase the entire project layout plan of other wings D & F were different were not obstructing my view from any window but suddenly the builder has changed the layout plan of other wings, which is now going to obstruct the view in the near future. Also we had been requesting the updated plan details from quite long but we were not shared saying it is still under discussion and we are awaiting approvals nor the total number of floors of other wings was shared with us. Also i have not yet signed any Builder Buyer agreement or any sort of sale deed, i would want to know how much amount is refundable in this case as i have opted for the cancellation. Also still in Rera the older project plan is visible and not the updated one. So can you also help us to understand as a buyer how much i have a say in if had been willing to buy as per the older project plan and no longer wish to continue because the project layout has been changed suddenly and it would obstruct my view in coming future.